What is a duodenal diverticulum?
A duodenal diverticulum (the plural of which is diverticula) is a pouch attached to the duodenum, the first part of the small intestine just past the stomach.
There are two types of duodenal diverticula. The common type which is present in some individuals, is one that sticks out from the duodenum, similar to the more common colonic diverticula. This is referred to as an "extramural" diverticulum. Extramural diverticula may vary in size from a few millimeters to a few centimeters. They usually are located in the area around the Papilla of Vater where the bile and pancreatic ducts enter the duodenum.
A second, rare type of diverticulum is referred to as an "intramural" diverticulum. It does not protrude from the duodenum. Rather, it protrudes into the duodenal lumen (the hollow inside of the duodenum through which digesting food flows). Both types of diverticula, extramural and intramural, communicate with the lumen of the duodenum so that contents of the duodenum can enter the diverticulum.
What causes a duodenal diverticulum?
The cause of extramural diverticula is not definitely known; however, they are believed to be acquired (not present from birth) due to a herniation (protrusion) of the duodenum through a defect in the muscle of the wall of the duodenum, perhaps in an area where arteries pass through the intestinal muscle to nourish the lining of the intestine.